President Trump promised to repeal and replace the Affordable Care Act “immediately” and “on Day 1” while on the campaign trail. But now, he claims he never said he’d get health care reform done quickly. (Peter Stevenson/The Washington Post)

After a smarting defeat on health care, President Trump is moving on to an ambitious bid to rewrite the U.S. tax code. But the ultra-conservative GOP lawmakers who stymied Trump on health care aren’t going away, and if Trump is to avoid a second major setback in Congress, he’ll need to win over far more of them this time around.

The “House Freedom Caucus,” as the few dozen members of the group call themselves, blocked Trump and Ryan’s health-care bill because it wasn’t conservative enough for them, offering too much in the way of benefits and interfering too much in the insurance market. When it became clear the vast majority of the group’s members were voting no, Trump — after a consultation with House Speaker Paul D. Ryan (R-Wis.) — pulled the bill.

The good news for Trump and Ryan, however, is that they and the House Freedom Caucus have, in their public statements, expressed broad areas of agreement on what to do with the tax code. There’s still, however, plenty of potential for conflict as Trump, Ryan and the caucus once again come together in search of a deal.

Here’s what the House Freedom Caucus’s members have said they’re looking for.

The big idea

Members of the group generally endorse the same basic principles for reform: Reduce tax rates for everyone. Then, to make up for some of the revenue the government is foregoing under those new rates, eliminate special deductions, exemptions and loopholes that allow certain categories of taxpayers to avoid paying taxes on portions of their income.

This has long been the position of conservative Republicans, and it is also the approach embodied in the plans proposed by Republicans, including Trump and Ryan. For instance, the plan Ryan and his colleagues in the House put forward last year would eliminate all deductions for individual taxpayers — except for the deductions for mortgage interest and charitable giving. Those deductions allow Americans to avoid taxes on money they pay in interest on their homes, along with any donations they make.

That plan might not go far enough for a conservative lawmaker like Rep. Thomas Massie (R-Ky.). In 2013, Massie told Bloomberg he supported a single tax rate for all taxpayers, with no exceptions whatsoever. “I love the flat tax, and I’m not afraid of getting rid of every deduction,” Massie said.

All the same, mainstream Republicans are basically in agreement with their party’s conservative faction when it comes to taxes — at least to a far greater degree than they were on health care.

Republicans believe health-care reform is still possible even after House leadership pulled the bill abruptly before it was scheduled for a vote. (Video: Alice Li, Jayne Orenstein/Photo: Melina Mara/The Washington Post)

The debt